mongrel73

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14 years, 108 days

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These are questions asked by mongrel73

Probably the easiest way to explain this is to show you what I want to do. I want to draw a contourplot which shows the contour lines going through the points [0,-1] and [3/4,-7/16] (these are the expression's stationary points).  The values of f at each of these points respectively are 1 and 101/128, so I have tried to display these contours, but when the graph comes up, the contour lines don't go through the point [3/4,-7/16], although they do go through [0,-1]. The code I'm trying to use is below.

f(x,y):=x^3-3*x*y+2*y^2-3*x+4*y+3;

I'm trying to make it animate slowly without having to click the 'decrease frame rate' button. Does anyone know if there's something I can put in the code to make it do this?

Thanks

The problem I'm having is that I have a large system of linear equations, the solution to which I know must be integers between 1 and 9. I have tried applying bounds etc., but the problem is that when I use solve, it said 'evaluating' for around half an hour, and still came out with nothing. Does anyone have any ideas as to how to make this faster, because I suspect that it's trying to find all solutions, and then eliminating the ones of the wrong form, rather than only looking for solutions where each variable is an integer between 1 and 9.

I have this system:
 

What I mean is, I have a set of variable, and a set of equations. The thing is, there are a lot of variables, and not enough equations to uniquely determine them unless the 'rules' are applied, which are:


1) all xi that exist are integers between 1 and 9, i.e. xi is in {1,2,3,4,5,6,7,8,9}

2) if xi exists, then xi<>xi+1 AND xi<>xi+10

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